For patients with respiratory disease the symptom of breathlessness (dyspnea) is the most frequent reason for seeking medical attention. Current methods for measuring the impact of breathlessness on activities of daily living rely on face-to-face interviews conducted by health care providers. Two common measures are the Baseline Dyspnea Index representing the severity of dyspnea at a single point in time, and the Transition Dyspnea Index representing changes in dyspnea compared with the baseline level before treatment. Despite widespread acceptance of these measures, the interview technique has been criticized on three counts: (1) selection of severity of breathlessness is made by the interviewer, not the patient, and thereby can increase measurement error (2) the method cannot be applied consistently in different medical centers because the same interviewers are not employed at all test sites (3) the process is expensive due to the cost of training and employing health care providers to conduct interviews and enter data into the computer. There is a need for a less expensive, standardized approach to the measurement of dyspnea that could be applied consistently throughout the world. The long term objective of this project is to develop such a method. The major aim of Phase I is to show that a computer-administered, standardized method completed by the patient yields results equivalent to those secured by interviews. Subjects employing the new method will be 100 patients diagnosed with chronic obstructive pulmonary disease. PROPOSED COMMERCIAL APPLICATIONS. There are excellent commercial prospects for computer software that allows the patient to rate their level of dyspnea associated with activities of daily living. Once the software package is implemented and tested, site licenses for acquiring the program will be sold to clinics, hospitals, and pharmaceutical companies worldwide.